1. Field of the Invention
The present disclosure relates to imaging, and more particularly to focal plane arrays such as used in imaging systems.
2. Description of Related Art
A typical focal plane array (FPA) has a system gain that is not constant as a function of temperature. System gain is important in producing accurate image data, and since the temperature of an FPA varies, e.g., based on changes in the environment external to the imaging system as well as changes in temperature due to changes in operation within an imaging system, variation in temperature gain can present a challenge to creating accurate image data. A typical solution for this problem is to utilize thermoelectric cooling to control the temperature of the FPA. As long as the thermoelectric cooling maintains a constant, known temperature at the FPA, and as long as the correct system gain at that temperature is known, the FPA can be used to produce accurate image data.
A typical focal plane array (FPA) also has pixel to pixel variation in behavior due to manufacturing variance and the like. This variation is typically addressed by calibrating each pixel and saving the pixel by pixel calibration data as a correction map used to correct signals from the pixels to produce accurate image data. Pixel performance varies as a function of temperature, and so the temperature at which the correction map is created is the temperature at which the system generates the most accurate images—changes in temperature at the FPA will reduce the effectiveness of the correction map. A typical solution for this problem is to use thermoelectric cooling to control the temperature of the FPA as described above. As long as the thermoelectric cooling maintains a constant, known temperature at the FPA, and using a correction map that corresponds to that known temperature, the FPA can be used to produce accurate image data regardless of ambient temperature.
Such conventional methods and systems have generally been considered satisfactory for their intended purpose. However, there is still a need in the art for improved imaging techniques. The present disclosure provides a solution for this need.